Some nice scopes there!
So to change the pupil distance on these scopes, you have to slew the UTA ring around to where you need it, is this how it is done?
Looking at that last picture, its looks to be quite a pain to move those rings with all those bolts holding them but I am only guessing.
The only drawback that I can see is that if you have to refocus anything, this will also affect your pupil distances, therefore requiring you to move those top rings, possilbly putting it slightly out of collimation each time